1. Field of the Invention
This invention relates to resistive memory elements and, more particularly, to creating an embedded resistive memory element from a high-k metal gate transistor structure.
2. Description of the Related Art
Microcontroller and logic chips require large blocks of embedded memory consisting of arrays of nonvolatile memory cells (devices). Each cell typically includes a transistor element as well as a memory element, such as a floating gate transistor or a variable resistor. Some memory elements, like the floating gate transistor, add additional process steps, such as a patterned polysilicon layer. Others, like certain variable resistor structures, use material films and structures that are incompatible with transistors and have to use extra fabrication steps to create them. For example, in one implementation, the resistive memory element is fabricated on top of the drain of the transistor element, which also adds steps to the overall fabrication process. Like other semiconductor devices, the cost and time required to fabricate embedded nonvolatile memory devices increases as the number of processing steps increases.
As the foregoing illustrates, what is needed in the art is a resistive memory cell design that can be fabricated more efficiently than previously disclosed resistive memory cells for embedded memories.